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Gary-
Before the second World War Zeiss Ikon and Carl Zeiss offered Distar and Proxar diopter lenses for the express purpose of extending the utility of their ground-glass focusing plate cameras. The Proxars effectively shortened the focal length, giving a wider field of view; The Distars, the opposite. The effect was modest, but real; it required ground glass confirmation with the camera on a tripod.
More recently, Distars have ceased to have much use (with one specific exception back in the '50's and '60's, too technical to get into here) while Proxars have taken on a new lease on life as closeup lenses on reflex cameras whose lenses have limited close focusing ability. (Prewar the close focusing job was taken care of by double or triple extension bellows.)
I wouldn't want to discourage your experiments with a Distar on a S Ik IV, but I would suggest that in the absence of any printed material, you will have to methodically develop your own charts. Simply use some frosted Scotch tape at the film plane, jam the shutter open (a rubber band holding the lever in the B position will do the trick, and, with the camera on a tripod, examine the image with a loupe, Ansel Adams style. Try different focus settings, f-stops, etc. I doubt you'll be able to extend the lens enough to be able to focus an infinity image, but this is a possiblity. Whatever else you might discover about using the Distar, you will gain an understanding of the image-making process and what affects it in what way. Enjoy yourself. You will also gain an appreciation of the practical advantage of a reflex camera in situations calling for close-up work.
Zeiss Historica has reprints of several historic booklets which might be of interest. Their website is in gestation but in the meantime contact the Secretary at 300 Waxwing Drive, Monroe Twp, NJ 08831.

Regards
Charlie Barringer
President of Zeiss Historica (among other things)

I will be using this lens on a Zeiss Ikon Super Ikonta IV with the
75mm 3.5f Tessar. I would be interested in light transmission loss
information, min./max focusing distances and/or depth of field charts
for this lens, and etc. or any information on where to find.
Thanks for the help,
Gary

charzou@... wrote:

Gary-
Before the second World War Zeiss Ikon and Carl Zeiss offered Distar and Proxar diopter lenses for the express purpose of extending the utility of their ground-glass focusing plate cameras. The Proxars effectively shortened the focal length, giving a wider field of view; The Distars, the opposite. The effect was modest, but real; it required ground glass confirmation with the camera on a tripod.
More recently, Distars have ceased to have much use (with one specific exception back in the '50's and '60's, too technical to get into here) while Proxars have taken on a new lease on life as closeup lenses on reflex cameras whose lenses have limited close focusing ability. (Prewar the close focusing job was taken care of by double or triple extension bellows.)
I wouldn't want to discourage your experiments with a Distar on a S Ik IV, but I would suggest that in the absence of any printed material, you will have to methodically develop your own charts. Simply use some frosted Scotch tape at the film plane, jam the shutter open (a rubber band holding the lever in the B position will do the trick, and, with the camera on a tripod, examine the image with a loupe, Ansel Adams style. Try different focus settings, f-stops, etc. I doubt you'll be able to extend the lens enough to be able to focus an infinity image, but this is a possiblity. Whatever else you might discover about using the Distar, you will gain an understanding of the image-making process and what affects it in what way. Enjoy yourself. You will also gain an appreciation of the practical advantage of a reflex camera in situations calling for close-up work.
Zeiss Historica has reprints of several historic booklets which might be of interest. Their website is in gestation but in the meantime contact the Secretary at 300 Waxwing Drive, Monroe Twp, NJ 08831.

Regards
Charlie Barringer
President of Zeiss Historica (among other things)

In a message dated Thu, 25 May 2000 2:40:12 PM Eastern Daylight Time, garcap@... writes:

<< I will be using this lens on a Zeiss Ikon Super Ikonta IV with the
75mm 3.5f Tessar. I would be interested in light transmission loss
information, min./max focusing distances and/or depth of field charts
for this lens, and etc. or any information on where to find.
Thanks for the help,
Gary

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Charlie, I wouldn't ever dispute your authority on matters with which I
myself was not personally involved, but your narration above has to be expanded
somewhat based on my own personal experience.

I myself bought Zeiss Proxar lenses 1x42 and 2x42 to use with my Contax-II,
back in 1938-1939. You'll recall that the f2 and f1.5 Sonnars used 42mm
slip-on auxiliary lenses and filters, as well as 40.5 mm screw-in filters.
The Contax-II with 5 cm lenses focussed down to 0.9 meters, as I
recall. It may have been 1.0 meter. With a 1x42 Proxar (i.e. 1 diopter, focal
length 1.0 meter), the camera, when set at infinity, focussed at 1.0 meter.
This extended the focussing distance DOWN from 1 meter, variable as the focussing
ring of the camera turned. The 2x42 Proxar extended it in still closer.

You may recall the Zeiss Depth of Field booklets which I owned for over 50
years and donated to your archives. Their primary purpose was to tell the
depth of field, for two different circles of confusion, for the Contax with all of
the lenses available for it. It is my recollection that those same booklets also
showed the focussing distance for Contax 5 cm lenses, with Proxars. I really
can't swear to that, as I haven't looked inside those booklets in 40 years or
more. If you have them handy, please give them a look.

And now finally: the mathematical relationships between lens setting distance and actual
focussing distance with Proxar added, are extremely simple. It isn't simple arithmetic
like add/subtract/multiply, but it ALMOST is. Any high school kid in elementary
algebra can handle it, and I think I saw it recently in one of the books I've been
reading. Possibly it was one of Kinglake's. If it were complicated I'd offer to generate
a whole bunch of tables, but it really isn't.

Best regards to all.....

Bill Lurie

I glossed over a couple of obvious points requiring unstated assumptions in my earlier statement.
1) Gary has a Distar, not a proxar. No camera not having a long extension bellows (or other focusing device) will be able to get an infinity (let alone closer) image with a negative diopter lens, because the lens cannot be extended from the film plane to its "new" infinity position. Practically speaking, the best way to check this is by viewing the virtual image at the film plane.
2) Proxars were used prewar on many Zeiss Ikon camera systems to allow closeup use on cameras with limited focusing racks or helicoids. Their use as close-up lenses became obvious only when the manufacturers incorporated rangefinder systems into their cameras, thereby limiting the focusing range from infinity to some fixed minimum (imposed by the rangefinding device) and allowing them to dispense with the tedious, if simple, method of groundglass viewing and focusing.
At the end of the day, all cameras using accessory lenses need to be focused on a groundglass (or with a clever device like the Contameter) and should be used with the camera immobilised on a tripod or other support.
As Bill Lurie pointed out to me, Rudolph Kingslake's early book, "Lenses in Photography" (1951) gives formulae and charts on this topic.
Sorry for the gaping inconsistencies.
Charlie

Gary-
Before the second World War Zeiss Ikon and Carl Zeiss offered Distar and Proxar diopter lenses for the express purpose of extending the utility of their ground-glass focusing plate cameras. The Proxars effectively shortened the focal length, giving a wider field of view; The Distars, the opposite. The effect was modest, but real; it required ground glass confirmation with the camera on a tripod.
More recently, Distars have ceased to have much use (with one specific exception back in the '50's and '60's, too technical to get into here) while Proxars have taken on a new lease on life as closeup lenses on reflex cameras whose lenses have limited close focusing ability. (Prewar the close focusing job was taken care of by double or triple extension bellows.)
I wouldn't want to discourage your experiments with a Distar on a S Ik IV, but I would suggest that in the absence of any printed material, you will have to methodically develop your own charts. Simply use some frosted Scotch tape at the film plane, jam the shutter open (a rubber band holding the lever in the B position will do the trick, and, with the camera on a tripod, examine the image with a loupe, Ansel Adams style. Try different focus settings, f-stops, etc. I doubt you'll be able to extend the lens enough to be able to focus an infinity image, but this is a possiblity. Whatever else you might discover about using the Distar, you will gain an understanding of the image-making process and what affects it in what way. Enjoy yourself. You will also gain an appreciation of the practical advantage of a reflex camera in situations calling for close-up work.
Zeiss Historica has reprints of several historic booklets which might be of interest. Their website is in gestation but in the meantime contact the Secretary at 300 Waxwing Drive, Monroe Twp, NJ 08831.

Regards
Charlie Barringer
President of Zeiss Historica (among other things)

In a message dated Thu, 25 May 2000 2:40:12 PM Eastern Daylight Time, garcap@... writes:

<< I will be using this lens on a Zeiss Ikon Super Ikonta IV with the
75mm 3.5f Tessar. I would be interested in light transmission loss
information, min./max focusing distances and/or depth of field charts
for this lens, and etc. or any information on where to find.
Thanks for the help,
Gary

------------------------------------------------------------------------
Old school buds here:

------------------------------------------------------------------------

Unsubscribe: ZICG-unsubscribe@...
Problems: mjm159@...

Charlie, I wouldn't ever dispute your authority on matters with which I
myself was not personally involved, but your narration above has to be expanded
somewhat based on my own personal experience.

I myself bought Zeiss Proxar lenses 1x42 and 2x42 to use with my Contax-II,
back in 1938-1939. You'll recall that the f2 and f1.5 Sonnars used 42mm
slip-on auxiliary lenses and filters, as well as 40.5 mm screw-in filters.
The Contax-II with 5 cm lenses focussed down to 0.9 meters, as I
recall. It may have been 1.0 meter. With a 1x42 Proxar (i.e. 1 diopter, focal
length 1.0 meter), the camera, when set at infinity, focussed at 1.0 meter.
This extended the focussing distance DOWN from 1 meter, variable as the focussing
ring of the camera turned. The 2x42 Proxar extended it in still closer.

You may recall the Zeiss Depth of Field booklets which I owned for over 50
years and donated to your archives. Their primary purpose was to tell the
depth of field, for two different circles of confusion, for the Contax with all of
the lenses available for it. It is my recollection that those same booklets also
showed the focussing distance for Contax 5 cm lenses, with Proxars. I really
can't swear to that, as I haven't looked inside those booklets in 40 years or
more. If you have them handy, please give them a look.

And now finally: the mathematical relationships between lens setting distance and actual
focussing distance with Proxar added, are extremely simple. It isn't simple arithmetic
like add/subtract/multiply, but it ALMOST is. Any high school kid in elementary
algebra can handle it, and I think I saw it recently in one of the books I've been
reading. Possibly it was one of Kinglake's. If it were complicated I'd offer to generate
a whole bunch of tables, but it really isn't.

Best regards to all.....

Bill Lurie



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Old school buds here:

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